Composite filter media utilizing bicomponent fibers

ABSTRACT

Disclosed is composite media that may be utilized in coalescing elements, coalescing cartridges, coalescing systems, and coalescing methods. The disclosed media typically is a composite or laminate material formed by bonding adjacent layers of media material comprising bicomponent fibers.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit under 35 U.S.C. § 119(e) toU.S. Provisional Patent Application No. 61/716,904, filed on Oct. 22,2012, the contents of which are incorporated herein by reference in itsentirety.

BACKGROUND

The disclosed subject matter relates to composite filter media. Inparticular, the disclosed subject matter is related to composite filtermedia in laminate form prepared by bonding adjacent layers of mediamaterial comprising bicomponent fibers. The composite filter media isuseful in industrial applications requiring long service life.

There is a demand for increasing the service interval for a filterwithout increasing the filter size, increasing the filter's pressuredrop, or decreasing the filter's capabilities for removing contaminant,in particular, filter performance requirements for high pressurefiltration applications, such as hydraulic and fuel filtration, areextremely demanding in terms of particulate removal, yet serviceintervals preferably are at least 250 hours, but ideally greater than500 hours, 1,000 hours, or even longer. To meet these pressure drop andlife requirements, specially engineered high performance filter media isneeded. The demanding removal and service life requirements of somefilter applications cannot be met with existing filter media andimproved filter media is desirable. In particular, improved compositemedia and methods for forming composite media are desirable.

SUMMARY

Disclosed is composite media that may be utilized in coalescingelements, coalescing cartridges, and coalescing systems and methods. Thecomposite media typically is formed by bonding at least three layers ofmedia material from an upstream direction to a downstream direction,namely Layer A, optionally Layer B. Layer C, and Layer D. The layerstypically have different characteristics and are designed to impartdesirable properties to the coalescing media. Typically, one or more ofthe layers comprise bicomponent fibers. The bicomponent fibers typicallycomprise different polymeric materials having different physical orchemical characteristics such as melting temperature.

In some embodiments of the disclosed composite media, at least one ofLayer A, Layer B, and Layer D comprise bicomponent polymeric fibershaving a core and a sheath, and Layer C comprises polymeric nanofibermaterial. The polymeric material of the sheath of the bicomponent fibersmay have a lower melting point than the polymeric material of the core.The polymeric material of the sheath of the bicomponent fibers also mayhave a lower melting point than the polymeric nanofiber material ofLayer C. The composite media material then may be formed by bonding thepolymeric nanofiber material of Layer C to the bicomponent fibers of atleast one of Layer A, Layer B, and Layer D by a method that includesheating the sheath material of the bicomponent fibers and melting thesheath material of the bicomponent fibers to the polymeric nanofibermaterial of Layer C.

Exemplary characteristics for the layers utilized to prepare thecomposite media are disclosed in Table 1. In some embodiments, Layer Acomprises polymeric media material having one or more of the followingcharacteristics: (a) a nominal mean fiber diameter of greater than about8, 9, or 10 μm; (b) a mean pore size of greater than about 10, 15, 20,or 25 μm; and (c) a permeability of greater than about 80 cfm.Optionally, Layer A comprises polymeric media material having one ormore of the following characteristics: (a) a permeability of 80-325 cfm;(b) a basis weight of 20-60 gsm; and (c) a thickness of 0.1-0.5 mm.

Layer B is optional. However, in some embodiments, Layer B is notoptional and Layer B comprises polymeric media material having one ormore of the following characteristics: (a) a nominal mean fiber diameterof 1-5 μm; (b) a mean pore size of 5-15 μm; (c) a basis weight of 15-50gsm; (d) and a permeability of 25-55 cfm. Optionally, Layer B comprisespolymeric media material, having one or more of the followingcharacteristics: (a) a maximum pore size of ≤30 μm; and (b) a thicknessof 0.1-0.5 mm.

In some embodiments, Layer C comprises polymeric media material havingone or more of the following characteristics: (a) a nominal mean fiberdiameter of 0.1-5, 0.1-3, or 0.1-1 μm; (b) a mean pore size of 0.1-15 or0.2-10 μm; and (c) a permeability of 3-55 cfm. Layer C may includenanofibers having a nominal mean fiber diameter of less than 1 μm andmay be otherwise referred to as a nanofiber layer. Optionally, Layer Ccomprises polymeric media material having one or more of the followingcharacteristics: (a) a maximum pore size of ≤10 μm; (b) a basis weightof 8-50 gsm; (c) and a thickness of 0.1-0.5 mm.

In some embodiments, Layer D comprises polymeric material having one ormore of the following characteristics: (a) a nominal mean fiber diameterof greater than about 8. 9, or 10 μm; (b) a mean pore size of greaterthan about 10, 15, 20, or 25 μm; and (c) a permeability of greater thanabout 40 cfm. Optionally, Layer D comprises polymeric media materialhaving one or more of the following characteristics: (a) a permeabilityof 40-200 cfm; (b) a basis weight of 40-200 gsm; and (c) a thickness of0.1-0.56 mm.

In some embodiments, the composite media has a permeability of less thanabout 40, 30, 20, 10, or 5 cfm. Preferably, the composite media formedfrom the multiple layers has a permeability of about 3-40 cfm.

The disclosed composite media may be further formed as pleated filtermedia. In some embodiments, the pleated filter media may be over-packed,for example, where the coalescing media has a pleat density D thatexceeds 1/(2H) where H is the thickness of the coalescing media. Wherethe composite media is pleated, it may be further configured to resistcollapsing of its pleats. In some embodiments, Layer D comprises mediamaterial that is textured and comprises grooves in a directionapproximately perpendicular to the pleated media bend lines in order toresist collapsing of the composite media's pleats.

The disclosed composite media may be utilized in coalescing elements,for example, coalescing elements configured for coalescing adiscontinuous liquid phase from a continuous liquid phase. In someembodiments, the coalescing elements are configured for method ofcoalescing water immersed in a liquid hydrocarbon (e.g., hydrocarbonfuel, biodiesel fuel, or lubricating, hydraulic, or transmission oil).The coalescing elements may be utilized in filter cartridges. Suitablecoalescing elements and filter cartridges that may comprise thedisclosed pleated coalescing media are disclosed in U.S. PublishedApplication No. 2011/0168621, published on Jul. 14, 2011, and U.S.Published Application No. 2011/0168647, published on Jul. 14, 2011, thecontents of which are incorporated herein by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides a schematic of one embodiment of high performancecomposite media as contemplated herein.

FIG. 2 provides exemplary configurations for the bicomponent fibersutilized in the presently disclosed composite media.

FIG. 3 illustratively provides definitions for terms used herein fordescribing a pleated form of the presently disclosed composite media.

FIG. 4 provides a schematic illustration of a cross-section of oneembodiment of pleated coalescing media as contemplated herein. (A)Normal pleat density, D<1/(2H); and (B) overpacked condition, D>1/(2H).

FIG. 5 provides a scanning electronic micrograph of a cross-section ofone embodiment of high performance composite filter media ascontemplated herein, showing the layers and a textured groove on thedownstream face of Layer D.

DETAILED DESCRIPTION

Disclosed herein is composite media formed from multiple layers of mediamaterial. The media may be further described based on the followingdefinitions.

Unless otherwise specified or indicated by context, the terms “a”, “an”,and “the” mean “one or more” or “at least one.” For example, “a layer”should be interpreted to mean “one or more layers.”

As used herein, “about”, “approximately,” “substantially,” and“significanitly” will be understood by persons of ordinary skill in theart and will vary to some extent on the context in which they are used.If there are uses of the term which are not clear to persons of ordinaryskill in the art given the context in which it is used, “about” and“approximately” will mean plus or minus ≤10% of the particular term and“substantially” and “significantly” will mean plus or minus >10% of theparticular term.

As used herein, the terms “include” and “including” have the samemeaning as the terms “comprise” and “comprising.”

The presently disclosed composite media typically is prepared frommultiple layers of bonded fibrous filter media. The fibrous filter mediatypically comprises polymeric fibers (i.e., synthetic fibers). FIG. 1shows one simplified schematic of the layers utilized to prepare acomposite media as contemplated herein. The composite media may beprepared from at least 4 layers of media material as shown in FIG. 1(Layers A, B, C, and D), but may include only 3 layers of media materialas described below (Layers A, C, and D). Exemplary properties of eachlayer of media material are shown in Table 1. The layers that form thecomposite media may be bonded by processes that include thermal bonding(e.g., via ultrasonic bonding, hot calendering, belt calendering,through-air thermal bonding, and radiant-heat bonding), and/or chemicalbonding (e.g., via the use of binders such as butadiene copolymers,acrylates, and vinyl copolymers).

In some embodiments, the disclosed media is a laminate filter mediaprepared by bonding a minimum of three (3) layers of media designed toprovide longer service life than conventional composite or laminatefilter media of equivalent contaminant removal characteristics withoutan increase in the size of the resultant filter element. The laminatefilter media may include: (1) a coarse, open upstream layer with largerpolymeric fiber designed to enable use of a pleated form of thecomposite media having over-packed pleat densities without significantdegradation in removal nor service live; (2) optional one or moretighter polymeric layer(s) with finer fibers designed to serve astransition layer(s) in gradient filtration and to protect the filtrationlayer from damage by laminating; (3) a polymeric micro- or nano-fiberlayer to provide high removal for fine particles at low pressure drop;and (4) a thin, coarse, open downstream layer with larger polymericfibers designed to facilitate relatively unrestricted flow through themedia under over-packed pleat densities without significant degradationin contaminant removal nor service life and to provide structuralsupport for upstream layers.

In the presently disclosed filter media, Layers A, B and D may providesupport and permit bonding of all the layers of the media into acomposite such that further support (such as a screen, cellulose orother stiffer material) is not required. Layer C is sandwiched betweenLayers B and D, or between Layers A and D, if there is no layer B. Theinclusion of optional Layer B as a transition layer with finer fibersthan Layer A and coarser fibers than Layer C yields media with nosignificant loss in contaminate removal or change in maximum pore size.Preferably, the fiber diameter of Layer B may be intermediate betweenthe fiber diameters of Layers A and C. Ideally, the fiber diameter ofLayer B may be between 1.5 and 4 times the fiber diameter of Layer C andless than the fiber diameter of Layer A. If additional layers areincorporated between A and C, then a more gradual transition in fiberdiameter from A to C is envisioned with each successive layer having asmaller fiber diameter than its preceding layer.

One or more of the layers of media material utilized to prepare thecomposite media typically comprises bicomponent fibers. As used herein,“bicomponent fibers” means fibers that are formed by extruding twodifferent polymers from the same spinneret with both polymers beingcontained with the same filament. The term “conjugate fibers” may beused interchangeably with “bicomponent fibers.” The bicomponent fibersutilized to prepare the presently disclosed composite media may have anysuitable configurations, including but not limited to, a core and sheathconfiguration and a side-by-side configuration. (See FIG. 2.)

Polymer materials that may be suitable for producing bicomponent fibersfor use in the presently disclosed composite media may include, but arenot limited to, polyesters (e.g. poly(ethylene terephthalate) (“PET”),poly(butylene terephthalate (“PBT”), poly(trimethylene terephthalate)(“PTT”), poly(ethylene naphthalate) (“PEN”),poly(cyclohexylenedimethylene terephthalate) (“PCT”), polylactic acid),polyamides (e.g., poly(hexamethylene adipamide) (“nylon 6,6”) andpolycaprolactam (“nylon 6,6”), co-polyamides, polyethylenes (e.g.,high-density polyethylene (HDPE) and linear low-density polyethylene(LLDPE), polypropylenes, polystyrenes, polyurethanes, andpolyoxymethylenes (i.e., acetal).

The bicomponent fibers may comprise two different polymeric materialshaving different melting temperatures. Wither regard to meltingtemperature (T), polymers typically have an “onset melting point” or“T_(omp)” and a “peak melting point” or “T_(pmp),” as determined bydifferential scanning calorimetry. Polymers have complex meltingtemperatures, unlike water-ice, and a T_(omp) and a T_(pmp) for a givenpolymer may be broadly defined by a temperature range. In someembodiments, the different polymeric materials may have onset meltingtemperatures that differ by at least about 10, 20, 30, 40, or 50° C. Inother embodiments, the different polymeric materials may have onsetmelting temperatures that differ by no more than about 60, 50, 40, 30,or 20° C. In further embodiments, the different polymeric materials mayhave onset melting temperatures that differ within a range oftemperatures (e.g., 10-60, 10-50, 10-40, 10-30, 10-20, 20-60, 20-50,20-40, 20-30, 30-60, 30-50, 30-40, 40-60, 40-50, or 50-60° C. Themelting temperatures of some polymeric materials that are suitable forpreparing the bicomponent fibers contemplated herein are shown in Table2. In some embodiments, where the different polymers have temperaturesranges for their T_(omp), the difference in T_(omp) for the two polymersmay be calculated by taking the highest temperature value for theT_(omp) of one polymer and subtracting this temperature value from thelowest value for the T_(omp) of the other polymer. For example, thebicomponent fibers might be formed from PBT having a T_(omp) of 220-230°C. and from Nylon 6.6 having a T_(omp) of 245-255° C. In this case, thehighest value for the T_(omp) of PCT is 230° C. and the lowest value forthe T_(omp) of Nylon 6,6 is 245° C., so the temperature difference maybe calculated as 245-230=15° C. This same calculation may be performedto determine the temperature difference between two T_(pmp)'s for twodifferent polymers, where the two different polymers have temperaturesranges for their T_(pmp)'s.

In the disclosed composite media, Layers A, B, C, and/or D may compriseor consist of bicomponent polymer fibers, ideally produced bymeltspinning to yield the appropriate fiber diameter as contemplatedherein. The bicomponent polymeric fibers of Layers A, B, C, and/or D,facilitate bonding of the layers in order to form the composite mediamaterial. Bicomponent polymeric fibers have been described (see, e.g.,WO2005059219A1), and typically comprise or consist of fibers, with a twoor more components in cross-section, such as a core and sheath (or skin)in cross-section. In such a configuration, the core is composed of adifferent polymer than the polymer of the sheath. As utilized in LayersA. B, and/or D of the filter media contemplated herein, the outermostsheath polymer may have a lower melting point than the innermost corepolymer and a lower melting point than the Layer C polymer. Thisconfiguration facilitates bonding (e.g., via ultrasonic bonding) ofLayer A, B, and/or D to Layer C while maintaining the integrity of LayerC, and also enables the use of less energy in the bonding process, whichin turn, may reduce damage to Layer C. This configuration also enableshigher melting point polymers to be used for the core, impartingcharacteristics to Layers A, B, C and/or D, as a whole, different thanwould be otherwise achievable. Such characteristics may include, but notbe limited to fiber diameter, stiffness, melting point, elasto-tensilestrength, and the like.

Composite media formed by bonding Layer A, optional Layer B. Layer C,and Layer D functions to resist premature plugging. Layer B is optional,however it is contemplated that there could be one or more layersbetween Layers A and C conforming to the characteristics and designpractices that are described herein.

The first upstream layer, Layer A, is more open and exhibits lowerparticle removal, than Layer B and succeeding layers upstream of LayerC. Each of these successive layers after Layer A exhibits higherparticle removal than its preceding layer. This is done by decreasingthe fiber diameter, porosity and/or pore size of each successive layer.Collectively, these layers are designed to provide progressively higherremoval for particles of a given size and to remove progressivelysmaller particles than the preceding layers. In addition to increasingservice life, Layers A and B secondarily protect the structure of theprimary filtration Layer C during manufacturing and processing of themedia. In some embodiments, Layer A may be meltspun or meltblownmaterial. In some embodiments, Layer B and succeeding layers upstream ofLayer C are preferably produced by meltblowing or meltspinning toproduce fibers with appropriate fiber diameter, pore size, particleremoval, and processing characteristics.

Layer C is primarily the filtration layer of the media and itsproperties may be configured for specific applications. Layer Ccomprises polymeric micro- or nano-fibers or a mixture of polymericmicro- and nano-fibers. Layer C typically has physical and particleremoval properties appropriate for the particular application.

Layer D provides support and protection during processing for theupstream layers. In such conventional media, Layer D typically comprisesor consists of relatively “open” media having sufficient strength tosupport the upstream layers of media under conditions of use. Layer Dalso facilitates processing of the upstream layers of media. Inpreparing the composite media, the integrity of the individual medialayers should be retained during compositing (i.e., after combining ofthe various media layers into the final laminate, each layer of thelaminate retains its individual characteristics).

The presently disclosed media may be configured as pleated coalescingmedia. (See FIGS. 3 and 4). The number of pleats per unit length in adirection normal to the flow and perpendicular to the pleats (i.e.,perpendicular to the depth of the pleats and pleated media bend lines),is referred to as pleat density, D. Overpacking occurs when the pleatdensity is so high that the media from opposing faces of a pleat touch.FIG. 4 schematically illustrates pleated media in a normal andoverpacked condition. The theoretical maximum pleat density forconventional filter media is limited by the thickness of the filtermedia, H, and is equal to 1/(2H). Overpacking refers to the condition inwhich the pleat density of a filter exceeds this theoretical maximumpleat density.

The presently disclosed composite media may be configured for use in avariety of coalescing or filtration applications such as pleatedconfigurations for use in fuel/water separator and hydraulic filterapplications. The presently disclosed composite media typically retainsits contaminant removal characteristics, yet resists premature plugging,even in an pleated, over-packed state.

The present inventors have discovered that the relative concentration offine particles smaller than about 5 μm is elevated in fuel and hydraulicfilter applications. In some embodiments of the presently disclosedcomposite media for use in fuel and hydraulic filter applications, thecomposite media may be configured as pleated media for removingparticles smaller than about 5 μm. Preferably, the media resistspremature plugging by elevated concentrations of particles smaller than5 μm and semisolids. Where pleated forms of the presently disclosedcomposite media are used in such applications, Layer C may be as thin aspractical while retaining the desired particle removal characteristics.This enables the use of pleated forms of the media in an over-packedcondition with high pleat densities to achieve the desired service life.

The presently disclosed media may be configured for use in filterelement as pleated media in an over-packed condition (i.e., whereD>1/(2H). Composite media suitable for use in over-packed filterelements may be obtained via a selected configuration of Layer D. Inconventional laminate filter media, Layer D provides support andprotection during processing for the upstream layers, in suchconventional media, Layer D typically comprises or consists ofrelatively “open” media having sufficient strength to support theupstream layers of media under conditions of use. Layer D alsofacilitates processing of the upstream layers of media. As disclosedherein, Layer D, as shown in Table 1, provides the additional functionof enabling the media to be used in an over-packed condition withminimal or no loss of effective filter media surface area, unlikeconventional laminate media. As disclosed herein, Layer D is intended tocompress at high pleat densities in a manner that minimizes the adverseeffects on pressure drop and contaminate removal. As such, Layer D mayserve as a “crumple zone,” such that the fluid flows parallel to thesurface of pleat, instead of normal to the surface as in conventionalmedia, with minimal increase in restriction in an over-packed condition.

In pleated configurations of the disclosed composite media, undesirablecompression of Layer D at high pleat densities may be minimized viausing a relatively large fiber diameter for the media of Layer D,texturing of the surface of Layer D, and minimizing the thickness ofLayer D. For example, Layer D may comprise polymeric fibers withgeometric mean diameter greater than 10 μm, and ideally greater than 40μm, typically produced by meltspinning or meltblowing. Additionally,Layer D may have an uncompressed thickness of less than 0.56 mm, andgenerally greater than 0.1 mm. Media with Layer D meeting theserequirements, even in compressed form, remains sufficiently open topermit fluid flow, thus exhibiting longer service life and moreefficient utilization of the filter media surface area compared to mediawithout such a layer. In an over-packed condition, existing filter mediaused to filter fluids enriched in particles smaller than about 5 μmexhibit heavy loading with contaminates near the pleat peaks but littleto no visible loading near the peak valleys. In contrast, over-packedmedia with Layer D as described herein exhibits nearly uniformcontaminant loading across the entire depth of the pleat.

Resistance to collapse for pleated forms of the composite media may befurther increased by texturing the downstream surface of Layer D. Thiscan be done by embossing or thermally processing the media to yield athree dimensional textured or grooved structure aligned in the machinedirection of the media on the downstream side of Layer D. In a filterelement utilizing such grooved media, the grooves of the media may bealigned in the machine direction of the media (i.e., in a directionapproximately parallel to the depth of the pleats, or perpendicular tothe pleated media bend lines), or the grooves may extend radially forcylindrical filter elements. Grooves or texture as shallow as about 0.1mm may be utilized.

In some embodiments of the disclosed composite media for fuel,hydraulic, and other demanding industrial applications, maximumthickness of Layer D is less than about 0.56 mm and a Layer D has agrooved surface. FIG. 5 shows a micrograph of a cross-section of Layer Das described in Table 1 having a grooved surface. Depending on thespecific characteristics of the composite media described in thisapplication, increases in pleat density from 11.1 to 32.0% may beachieved along with corresponding increases in capacity and servicelife. These increases in capacity and service life may be achieved byusing the media in an over-packed condition.

In specific embodiments, the composite media may be prepared from LayerD comprising or consisting of polymeric filter media with the followingproperties: (1) a fiber diameter greater than 10 μm, mean pore sizegreater than 20 μm, permeability greater than 40 cfm, and thickness lessthan 0.56 mm to enable significantly higher pleat density andcorrespondingly higher contaminant holding capacity and service life;(2) a capability of being over-packed, i.e., where the pleat density isin excess of the 1/(2H), without significant performance penalty; and(3) optionally, comprising or consisting of bicomponent fibers.

In some embodiments of the composite media, Layer A need not be as thickas Layer D. However, Layer A must still have high enough porosity andlarge enough fiber diameter, to allow flow to pass through the layer ina direction essentially parallel to the surface of Layer C with minimalrestriction. If Layer A does not have high enough porosity and largeenough fiber diameter, restriction may be excessive and over 50 percentof the media may not be fully utilized, as shown in FIG. 4. The physicalcharacteristics described herein enable the use of over-packed media toincrease the optimal pleat density. Thus, increased useful filter mediasurface area and service life can be achieved for demandingapplications, like lube, hydraulic and fuel filtration where thecontaminant size distribution is dominated by particles finer than about5 μm.

In particular, the disclosed laminate media may include a Layer Acomprising or consisting of polymeric filter media with the followingproperties: (1) a fiber diameter greater than 8 μm, mean pore sizegreater than 25 μm, permeability greater than 80 cfm, and thickness lessthan 0.50 mm to enable significantly higher pleat density andcorrespondingly higher contaminant holding capacity and service life;(2) a capability of being over-packed, i.e., where the pleat density isin excess of the 1/(2H), without significant performance penalty; and(3) optionally, comprising or consisting of bicomponent fibers. Inparticular, the disclosed laminate media may include a Layer A and/or aLayer D, as just described.

Exemplary configurations of layers for preparing the composite mediadisclosed herein are disclosed in U.S. Published Application No.2011/0168621, published on Jul. 14, 2011, and U.S. Published ApplicationNo. 2011/0168647, published on Jul. 14, 2011, the contents of which areincorporated herein by reference. These applications disclose amultilayer media having one or more of the following characteristics:Layer A: nominal mean fiber diameter >10 μm; mean pore size >50 μm;maximum pore size >100 μm; permeability 225-325 cfm; thickness 0.3-0.5mm; and basis weight 48±10 gsm. Layer B: nominal mean fiber diameter1.0-5.0 μm; mean pore size 5.0-15.0 μm; maximum pore size 10.0-25.0 μm;permeability 35-55 cfm; thickness 0.1-0.3 mm; and basis weight 38±10gsm. Layer C: nominal mean fiber diameter 0.1-0.8 μm; mean pore size1.0-8.0 μm; maximum pore size 1.0-10.0 μm; permeability 3.0-20.0 cfm;thickness 0.1-0.3 mm; and basis weight >20 gsm. Layer D: nominal meanfiber diameter >40 μm; mean pore size 30-35 μm; maximum pore size 40-65μm; permeability 50-75 cfm; thickness 0.45-0.65; and basis weight 198±20gsm.

Composite filter media as disclosed herein was tested using PTI 0-5 μmtest dust, which is a surrogate for the contaminants found in actualfuel applications, and using ISO Fine Test Dust, which is a coarsercontaminant specified in SAE fuel filter test standards. With ISO Fine,the capacity of over-packed elements was reduced by large particlesloading the upstream portion of pleats and the full media surface areawas not fully utilized. With PTI 0-5 μm dust, full utilization of thesurface area and higher capacity was obtained when the fiber diameter ofthe media in Layer A was greater than about 8 μm, but not when finerfibers were used for Layer A.

In the foregoing description, it will be readily apparent to one skilledin the art that varying substitutions and modifications may be made tothe invention disclosed herein without departing from the scope andspirit of the invention. The invention illustratively described hereinsuitably may be practiced in the absence of any element or elements,limitation or limitations which is not specifically disclosed herein.The terms and expressions which have been employed are used as terms ofdescription and not of limitation, and there is no intention that in theuse of such terms and expressions of excluding any equivalents of thefeatures shown and described or portions thereof but it is recognizedthat various modifications are possible within the scope of theinvention. Thus, it should be understood that although the presentinvention has been illustrated by specific embodiments and optionalfeatures, modification and/or variation of the concepts herein disclosedmay be resorted to by those skilled in the art and that suchmodifications and variations are considered to be within the scope ofthis invention.

Citations to a number of references are made herein. The citedreferences are incorporated by reference herein in their entireties. Inthe event that there is an inconsistency between a definition of a termin the specification as compared to a definition of the term in a citedreference, the term should be interpreted based on the definition in thespecification.

TABLE 1 Exemplary Media Layers and Properties of Laminate Media NominalMean Mean Fiber Pore Maximum Basis Diameter Size Pore Size PermeabilityThickness Weight Layer Material (μm) (μm) (μm) (cfm) (mm) (gsm) APolybutylene  >8 >25 >30 80-325 0.1-0.5 20-60 terephthalate BPolybutylene   1-5 5-15 10-25 25-55  0.1-0.5 15-50 terephthalate CPolyamide 0.1-5 1-15  1-25 3-55 0.1-0.5  8-50 D Polyethylene >10 >20 >4040-200 0.10-0.56  40-180 terephthalate

TABLE 2 Peak Onset Melting Point Melting point Material (T_(omp)), ° C.(T_(pmp)), ° C. PBT 220-230 223-230 PET (film grade) 240-250 250-260 PET(Meltblown grade) 200-220 210-230 PTT 215-235 225-235 PEN 255-265265-275 PCT 275 285 PLA 140-150 150-160 co-polyamides (PA 4,14) 200-210210-220 PA46 280 285 polycaprolactam 220-235 225-235 (Nylon 6)poly(hexamethylene adipamide 245-255 255-265 (Nylon 6,6) PA610 200-210210-220 PA612 210-220 220-230 PA11 145 155 PA12 120-130 130-140 PPS(Polyphenylene sulfide) 275-280 285-290 PTFE (polytetrafluoroethylene)315-320 325-330 PVDF Polyvinylidene Fluoride) 160-165 170-175

We claim:
 1. A composite media comprising: at least three layers of media material, the at least three layers of media material bonded together and include, from an upstream direction to a downstream direction, a Layer A, a Layer C, and a Layer D, wherein one or more layers adjacent to the Layer C consists of bicomponent polymeric fibers, wherein the Layer A comprises polymeric media material having a nominal mean fiber diameter of greater than about 10 μm; the Layer C comprises polymeric media material comprising nanofibers and having a mean pore size of 0.2-10 μm; and the Layer D comprises polymeric media material having a nominal mean fiber diameter greater than about 10 μm and provides support for the preceding layers, wherein the composite media is configured as a pleated filter media, wherein the pleated filter media has a pleat density that exceeds 1/(2H), wherein H is a thickness of the composite media, and wherein the polymeric media material of Layer D is textured and comprises grooves in a direction perpendicular to bend lines in pleats of the Layer D.
 2. The composite media claim 1, wherein the bicomponent polymeric fibers comprise two different polymeric materials, wherein one of the two different polymeric materials has a different onset melting point than an onset melting point of another of the two different polymeric materials.
 3. The composite media of claim 2, wherein the onset melting points of the one of the two polymeric materials and the other of the two different polymeric materials differ by at least 10° C.
 4. The composite media of claim 1, wherein the bicomponent polymeric fibers comprise a core and sheath in cross-section, the core and sheath each comprise a polymeric material, wherein the polymeric material of the core is a different polymeric material than the polymeric material of the sheath, and wherein the polymeric material of the sheath has a melting temperature that is lower than a melting temperature of the polymeric material of the core.
 5. The composite media of claim 4, wherein the Layer A consists of the bicomponent polymeric fibers, and the melting temperature of the polymeric material of the sheath is lower than a melting temperature of the polymeric media material of the Layer C.
 6. The composite media of claim 4, further comprising a Layer B disposed between the Layer A and the Layer C, wherein the Layer B consists of the bicomponent polymeric fibers, and the melting temperature of the polymeric material of the sheath is lower than a melting temperature of the polymeric media material of the Layer C.
 7. The composite media of claim 4, wherein the Layer D consists of the bicomponent polymeric fibers, and the melting temperature of the polymeric material of the sheath is lower than a melting temperature of the polymeric material of the Layer C.
 8. The composite media of claim 4, wherein the Layer A and the Layer D consist of the bicomponent polymeric fibers, and the melting temperature of the polymeric material of the sheath is lower than a melting temperature of the polymeric material of the Layer C.
 9. The composite media of claim 4, further comprising a Layer B disposed between the Layer A and the Layer C, wherein the Layer A, the Layer B, and the Layer D consist of the bicomponent polymeric fibers, and the melting temperature of the polymeric material of the sheath is lower than a melting temperature of the polymeric material of Layer C.
 10. The composite media of claim 1, wherein one or more layers are bonded to one or more adjacent layers via ultrasonic bonding.
 11. The composite media of claim 1, wherein the Layer A comprises polymeric media material having a mean pore size of greater than about 25μm.
 12. The composite media of claim 1, wherein the Layer A comprises polymeric media material having a maximum pore size of greater than about 30 μm.
 13. The composite media of claim 1, wherein the Layer A comprises polymeric media material having a permeability of 80-325 cfm.
 14. The composite media of claim 1, wherein the Layer A comprises polymeric media material having a thickness of 0.1-0.5 mm.
 15. The composite media of claim 1, wherein the Layer A comprises polymeric media material having a basis weight of 20-60 gsm.
 16. The composite media of claim 1, wherein the Layer C comprises polymeric media material having a nominal mean fiber diameter of 0.1-5 μm.
 17. The composite media of claim 1, wherein the Layer C comprises polymeric media material having a maximum pore size of 1-25 μm.
 18. The composite media of claim 1, wherein the Layer C comprises polymeric media material having a permeability of about 3-55 cfm.
 19. The composite media of claim 1, wherein the Layer C comprises polymeric media material having a thickness of 0.1-0.5 mm.
 20. The composite media of claim 1, wherein the Layer C comprises polymeric media material having a basis weight of 8-50 gsm.
 21. The composite media of claim 1, wherein the Layer D comprises polymeric media material having a nominal mean fiber diameter greater than 15 μm.
 22. The composite media of claim 1, wherein the Layer D comprises polymeric media material having a mean pore size greater than 20 μm.
 23. The composite media of claim 1, wherein the Layer D comprises polymeric media material having a maximum pore size greater than 40 μm.
 24. The composite media of claim 1, wherein the Layer D comprises polymeric media material having a permeability of 40-200 cfm.
 25. The composite media of claim 1, wherein the Layer D comprises polymeric media material having a thickness of 0.1-0.56 mm.
 26. The composite media of claim 1, wherein the Layer D comprises polymeric media material having a basis weight of 40-180 gsm.
 27. The composite media of claim 1, further comprising a Layer B disposed between the Layer A and the Layer C, wherein the Layer B comprises polymeric media material having one or more of the following characteristics: (a) a nominal mean fiber diameter of 1-5 μm; (b) a mean pore size of 5-15 μm; (c) a maximum pore size of 10-25 μm; (d) a permeability of 25-55 cfm; (e) a thickness of 0.1-0.5 mm; and (f) a basis weight of 15-50 gsm.
 28. The composite media of claim 1, further comprising a Layer B disposed between the Layer A and the Layer C, wherein at least one of the Layer A, the Layer B, the Layer C, and the Layer D comprises polymeric material selected from a group consisting of polyamide material, polybutylene terephthalate material, polyethylene terephthalate material, and polyester material.
 29. The composite media of claim 1, wherein the one or more layers adjacent to the Layer C consists of bicomponent polymeric fibers that have been meltspun or meltblown.
 30. The composite media of claim 1, wherein the Layer C comprises polyamide material.
 31. The composite media of claim 1, further comprising a Layer B disposed between the Layer A and the Layer C, wherein at least one of the Layer A and the Layer B comprise polybutylene terephthalate material.
 32. The composite media of claim 1, wherein the Layer D comprises polyethylene terephthalate material. 